In many technical systems, it is advantageous to know and track the position of individual devices, referred to in the following as nodes. Whereas in the open, GPS can be used for this purpose, for example for vehicle navigation, other methods are required in buildings or inner cities. Examples of suitable applications or systems are fire alarm sensors in buildings, sensors or actuators in a production system, sensor nodes in a wireless sensor network or mobile terminals in an ad hoc radio network. Furthermore, it is advantageous if the components or nodes form a communication network and are able to independently determine their position without a central entity, for example a localization server. Finally, it is also advantageous if the least possible infrastructure has to be assumed for position determination, i.e. if for example only a few anchor nodes with a known position have to be provided.
Known decentralized methods for position determination presume anchor nodes, i.e. nodes whose position is always known. This requires an installation cost and presumes that the positions of the individual anchor nodes are compatible, i.e. that their positions in the same coordinate system are known.
The only known method that functions without anchor nodes is the “GPS Free Positioning System” from Capkun et al., Swiss Federal Institute of Technology, Lausanne. The disadvantage with this method is, however, that it is described in only two dimensions, and because it is based on a local triangulation cannot therefore completely take account of redundant information.